Mining machine



April 7, 1942- R. K. JEFFREY 5 5 MINING MACHINE Filed June 21, 1938 '7 Sheets-Sheet 1 f/WENTOR: ROBERT KJEr-"FREY,

RI .K. JEFl- REY MINING MACHINE April 7, 1942 Filed June 21, 1958 7 Sheets-Sheet f/vyf/vroR. ROBERT KJEFFREY,

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April 7, 1942.

MINING MACHINE 7 Sheets-Sheet 3 V Filed June 21, 1938 f/WENTOR. ROBERT K.JEF=FREY,

April 1942- v R. K. JEFFREY 2,278,656

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Filed June 21, 1938 7 Sheets-Sheet 6 f/YVENTOR ROBERT K.JEFFRE(, BY MM; 7%.MI

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ROBERT K. JEFFREY,

G M m No. n9

ATT'Y.

Patented Apr. 7, 1942 MINING MACHINE Robert K. Jeffrey, Columbus, Ohio, assignor to The Jeffrey Manufacturing Company, a corporation of Ohio Application June 21, 1938, Serial No. 214,959

Claims.

This invention relates to a mining machine adapted to slide over a mine floor while cutting a kerf and an object of the invention is to provide improved mean for adjusting the inclination of said mining machine to determine the p th of travel of the cutter bar.

Another object of the invention is to provide I .an improved hydraulic mechanism for.levelling or adjusting the plane of a mining machine to compensate for irregularities in the mine floor or irregularities in the plane of a coal band or a dirt band.

A further object of the invention is to provide an improved control valve for a hydraulic system which is particularly useful in controlling a mining machine.

Still another object of the invention is to provide an improved form of hydraulic pump particularly adapted for use in a mining machine.

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.

In the accompanying drawings,

Fig; 1 is a plan view of the mining machine comprising my inventionwith part of the cutter bar broken away;

Fig. 2 is a side elevational view of the apparatus of Fig. 1;

Fig. 3 is an enlarged plan view of the forward section of the mining machine comprising my invention with the top cover plate removed and with, parts shown in section;

Fig. 4 is a sectional elevational view taken on the line l4 of Fig. 1', looking in the direction of the arrows;

Fig. 5 is a detailed sectional elevational view taken on the line I5 of Fig. 1, looking in the direction of the arrows;

Fig. 6 is a sectional elevational view taken on the line 6-5 of Fig. 1, looking in the direction of the arrows;

Fig. 7 is a transverse sectional elevational view taken on the line l-l of Fig. 1, looking in the direction of the arrows;

Fig. 8 is a sectional elevational view through the control valve comprising a feature of my invention;

Fig. 9 is an end elevational view of the control valve of Fig. 8;

Fig. 10 is a planview of the control valve of Fig. 8;

Fig. 11 is an enlarged plan view of the pump comprising a-feature of my invention;

Fig. 12 is a sectional view taken on the line |2-l2 or Fig. 11, looking in the direction of the arrows;

Fig. 13 is a sectional view taken on the line l3.-l3 of Fig. 11, looking in the direction of the arrows;

Fig. -14. is a schematic illustration of the hydraulic control system withthe control valve in one position of adjustment;

Fig. 15 me. complete schematic showing or pip- 1 ing diagram ofthe hydraulic control system with the control valve in a different position of adment from that illustrated in Fig. 14;

Figs. 16, 17 and 18 are similar to Fig. 14 showing three other positions of adjustment of the control valve;

Fig. 19 is a side elevational view of one of the skids connected to the bottom of the mining machine; and

Fig. 20 is an enlarged view of the means for detachably connecting one end of each of the skids to the bottom of the mining machine.

The invention herein disclosed represents an improvement on the invention disclosed and claimed in Patent No. 2,091,405 of R. K. Jeffrey et al., for aMining machine, dated August 31, 1937, and Patent No. 2,091,416 of L. E. Mitchell for a Mining machine, dated August 31, 1937.

It will be understood that structural details not herein disclosed in the fullest detail follow the disclosures of the two above mentioned patents.

The mining machine comprising my invention is formed by a main frame 26 made up of the tail section 2|, the motor section 22 and the head section 23. Said sections 2|, 22 and 23 are bolted together and may be taken apart by the simple expedient of removing nuts 24. The tail section 2| follows the structure disclosed in the above mentioned patents. It therefore needs no particular description except for that hereinafter given 1 in connection with Fig. 5 of the drawings which does represent one novel feature of my invention; It may be stated in passing, however, that said,

tail section 2| includes a pair of cable drums 25 and 26 with which are associated cables 21 and 28, respectively, which may be operated to drag the mining machine over a mine floor to eflect a mining operation or to move the mining machine from place to place. The motor section 22 likewise follows the structure of each of the above mentioned patents and therefore needs no special description.

Extending along the bottom and side edges of the main frame 20 is a pair of skids 29 and 30, (Figs. 7, 19 and 20), the rear end of which has a diagonally positioned oval head 30' adapted to hydraulic motors 3| and 32, respectively, which follow in structure the disclosures of each of said above mentioned patents. The structures of the two motors 3| and 32 are similar and in the interest of a complete description motor 3| may be briefly described as follows. Said motor 3| comprises a removable cylinder 33 tightly received in a cylindrical opening in the main frame of the head section 23 and provided with a downwardly extending centrally positioned rod 34 having a head 35. Within the cylinder 33 is a piston 36 provided with seal rings 31 which may be clamped to the piston 36 in a receiving groove by a threaded clamping member 38 which has threaded relation with the piston 36. The head of the rod 34 cooperates with a seat 39 in the bottom of the piston 36 and a ledge 48 on the bottom of the clamping member 38 to determine the limits of movement of the piston 36. Adjacent its bottom, piston 36 is provided with a pair of downwardly extending arms 4|, 4| (see Fig. 1)

adapted to receive a pin 42 to provide a, pivotal connection with an upstanding lug 43 on the skid 29. It will thus be evident that vertical adjustment of the piston 36 will provide for pivotal movement of the skid 29 about its rear end to adjust the elevation and inclination of one side I and as a consequence, the height and/or inclination of the kerf cutting mechanism may also be adjusted. The improved hydraulic system whichI have provided for operating the motors 3| and 32 is described in detail hereinafter.

Mounted upon the lower forward portion of the head section 23 is a kerf cutting mechanism comprising a cutter bar 44 rigidly attached to an adjusting plate 45, as by welding, which plate 45 is pivotally mounted upon the bottom plate 46 of the head section 23 for lateral adjustment about the axis of the hereinafter described kerf cutter chain drive shaft.

To maintain the adjusting plate 45 attached to the bottom plate 46 while providing for their adjustment, I provide cooperating ledge plates 41 and 48 which are attached, respectively, to the plates 45 and 46. The adjusting plate 45 is provided with a plurality of spaced apertures as disclosed in full detail in the above mentioned patents, adapted to receive selectively one of a pair of locking pins 49 carried by a projection 58 on the front of the head section 23.

Associated with cutter bar 44 in a well known manner is a kerf cutting chain 5| provided with appropriate cutter bits and adapted to be driven by a drive sprocket 52'keyed to a drive shaft 53 which is journaled in the head section 23 by bottom anti-friction roller bearing 54 and top antifriction roller bearing 55, the latter of which is carried in a pocket in the removable top plate 55 of the head section 23 and held in place by a removable cover plate 51.

Driving of the shaft 53 is effected from a worm gear 58 through a clutch comprising jaws 59 mounted on said worm gear 58 and shiftable clutching element 60 feathered on a cup 6| which is welded to the shaft 53 as at 62. A shipper 63 operated by a yoke 64 which is controlled by a toggle and link mechanism 65 (see Fig. 6) is provided to effect engagement and disengagement of the clutch to effect a driving or nondriving relation between the worm gear 58 and the drive shaft 53. An operating rod 66 is provided for the toggle and link mechanism 65 which extends to an operator's position adjacent the tail section 2| of the mining machine. The construction of the toggle and link mechanism, as

well as the clutch, follows the disclosure of the two above mentioned patents.

To effect a seal, thereby to prevent a loss of oil from the head section 23, I provide a grease 52 and which is adapted to be filled with lubrieating oil at all times, and the second of which houses hydraulic control mechanism for the piston motors 3| and 32, hereinafter described in iull detail. The third of said compartments is a gear compartment, as hereinafter described in more detail.

It may be mentioned that the compartments 1| and 12 are provided with a common removable top plate 13 by which access is gained to the interior thereof.

Mounted within the partition 68 and formin a part thereof is a hydraulic oil pump 14, the structure of which is disclosed in full detail in Figs. 3, 11, 12 and 13 of the drawings. Said pump 14 comprises a main frame or casting 15 provided with a flange 16 adapted to rest against the partition 88 and provided with a pair of spaced vertical counter-bored holes 11, 11 adapted to receive screws 18 (see Fig. 3), to attach the casting 15 rigidly to the adjacent enlarged portion of'the partition 68. g

The casting 15 is also provided with a horizontally positioned angularly extending bore 19 which forms the cylinder of the pump 14. For purposes of manufacture, the bore 19 extends completely through the casting 15 and through an extending tapered neck portion 88 thereof and one end is threaded at 8| to receive a nipple of the check valve 82 (see Fig. 3). The bore 19 communicates with achamber 83 intermediate its ends, which chamber 83 is formed by a vertical bore the top portion of which is closed by a threaded plug 84 to prevent the formation of an V airdome.

Within the cylindrical bore 19 I position a piston or plunger 85 provided with spaced oil grooves 86, 86 which extends through the neck portion 8|) and is provided with a bearing head 81. Surrounding the neck 88 is a coil spring 88 one end of which bears against the head 81 and theother against a boss of the casting 15 tending to move the piston 85 outwardly or to the right as viewed in Figs. 11 and 12.

To reciprocate the piston 85, and particularly to move it against the action of the spring 88,

2,278,656 I provide an eccentric cam 89 which is rigidly,

attached to the worm gear 68 by appropriate screws, as clearly illustrated in Figs. 3 and 4 of the drawings. It is thus to be seen that the worm gear 58 which is in the gear train for driving a kerf-cutting mechanism, including the cutter chain 5|, is also employed to drive the hydraulic pump I4.

As clearly illustrated in Fig. 3 of the drawings, there is associated with the threaded portion 8| a check valve 82 which permits oil to flow into the chamber 83 under the suction influence of the retreating piston 85 but prevents oil from flowing outwardly therefrom through the threaded port 8| under the influence of the inward movement of said piston 85. In other words, the

. check valve 82 controls the inlet of fluid to the chamber 83.

The out-put of the fluid from the chamber 03 is afforded by way of a horizontal passage 90 which communicates with chamber 83 and which is closed by a plug 9|. Passage 90 communicates with a vertically disposed port 92 leading to a chamber 93 which, in turn, communicates with outlet passage 94 leading to an internally threaded boss 95 adapted-to receive the pressure line of the hydraulic control system, as hereinafter described in full detail.

A removable ball check valve 96 is associated with the port 92 and provides for free flow of oil to the passage 94 from the passage 90 but prevents a reverse flow thereof. In other words, the check valve 96 controls the proper outward flow of fluid from the pump I4 to the out-put or pressure line. It will thus be seen that upon operation of thecam 89, which operates whenever the driving motor is in operation without regard to whether the kerf-cutter is in operating or non-operating condition, the hydraulic pump I4 will be operated tosupply pressure to the hydraulic control system for the piston motors 3| and 32, as hereinafter described in full detail.

Before describing in detail the control valve which controls the operation of the hydraulic piston motors 3| and 32, attention is directed particularly to Figs. 3, 4, 7 and 10 and to the general system for controlling said piston motors 3| and 32. It is to be noted that within the compartment II there is formed an oil sump 91 (see Fig. 4) in the bottom of which is positioned an oil strainer98 connected by a feed pipe 99 to the previously described check valve 82. This provides for the feeding of oil or other hydraulic medium to the pump 14, it being understood that the sump 91 is maintained full of oil or at least at a level above the strainer 98 at all times.

Leading from the boss 95 of the pump I4 is the pressure line or pipe I 00' which is connected to said boss 95 by an appropriate threaded nipple. The pressure line I00 is connected to ablock |0I by an appropriate nipple which block MI is provided with a horizontal through passage leading to an outlet pressure pipe I02 which, in turn, leads to the pressure boss I03 of the control valve I04 illustrated in detail in Figs. 8, 9 and 10. From the control valve I04 a feed pipe I05 leads to the hydraulic piston motor 3| and a feed pipe I06 leads to hydraulic piston motor 32.

It may be stated generally that by operation of the control valve I04 oil under pressure supplied thereto by the pump I4 may be diverted either to the sump 91 or to selected ones of the piston motors ,3I or 32, as hereinafter described in full detail.

Also associated with the block |0I and in communication with the previously described longitudinal passage thereof which connects the pressure pipes I00 and I02 is an upwardly extending passage leading to a pressure relief valve I01 adapted to discharge oil to the sump 9'! whenever excessive pressure is realizedin the pressure line I00.

As hereinafter described in full detail, the pressure relief valve I01 is to take care of an emergency condition because in normal operation a low pressure by-pass is provided for the pump I4 thereby providing for its operation at substantially no-load except when it is doing useful work.

Before proceeding with the description of the control valve I 04, attention is directed to the drive forthe worm gear 59 which is illustrated particularly in Figs. 3 and '7 of the drawings. As clearly illustrated in Fig. 3, a worm I08 carried by a shaft I09 meshes with the worm gear 58. Shaft I09 is mounted in anti-friction bearings I I0 and I I I, the latter being carried by partition 68. At its rear end the shaft I09 has keyed thereto. a pinion II2 which is housed in compartment 12 and meshes with the drive pinion, not illustrated, on the end of the.armature shaft of the electric motor carried within motor section 22, which .shaft extends into compartment I2. It is thus to be seen that whenever the electric motor of the mining machine is in operation there will be a driving connection to the cam 89 which will cause the pump I4 to provide fluid pressure for operating the hydraulic piston motors 3| .and.32. This is independent of the operation of the kerf-cutting mechanism though, of course, the hydraulic system may be operated at the same time that the kerf-cutting mechanism is in operation.

.Before proceeding with the description of the detailed structure of the control valve I04, it is to be noted that the block I 0| is carried by a bracket II? (see Figs. 3 and 4), bolted to the bottom plate 46 of the section 23 above the sump 91 and within the compartment II. The control valve I04 is also within the compartment II and bolted to the bottom plate 46 of section 23, as

clearly illustrated in Fig. 3 of the drawings. It

is thus to be seen that the control valve I04, pressure relief valve I01 and the block IOI, the pump I4, as well as all of the connecting pipes or lines, except part of the feed pipe I06, are within the compartment II where they are fully enclosed and protected.

As clearly seen in Figs. 8, 9 and 10 of the drawings, the control valve I04 comprises a main body or casting comprising a base II4, a pair of rearwardly extending arms I I5, I I5 and a cylindrical member I I6. The cylindrical member I I6 is provided with a horizontal longitudinally extending cylindrical bore II'I adapted to receive a sliding piston or plunger II8 provided with spaced end oil sealed grooves II9. I I9. The cylindrical member II Scarries a previously mentioned pressure boss 103 which is connected to pressure pipe I02 and carries bosses I20v and I2I connected, respectively, to previously mentioned feed pipes I05 and I06. Boss I03 is provided with a pair of pressure passages I22 and I23 leading to pressure chambers I24 and I25, respectively, formed in cylindrical member 6. Boss I20 is provided with a feed passageway I26 leading to feed chamber I21 and boss I2I is provided with feed passage I 28 leading to feed chamber I29. Intermediate its ends the cylindrical member H6 is also provided with a vertical bore I30.

It may be stated that thei'eed chamber I21, pressure chamber I24, bore I30, pressure chamber I25 and feed chamber I29 are spaced progressively from the rear end to the front end of the cylindrical member H6 and each is spaced the same distance from the next successive one so that upon giving five equal movements to the piston II8 a selected point will progressively move from chamber I21 to chamber I29 in the sequence above set forth for the purpose hereinafter described in full detail.

The piston H8 is provided with a longitudinally extending bore I3I which is closed by a plug I32 and communicates with a pair of horizontally extending ports I33 and I34, midway between which is a vertically extending port I43, which ports I33, I43 and I34 are spaced apart equal distances which distances are equal to those between chambers I21 and I24, chamber I24 and bore I30, bore I30 and chamber I25, and chambers I25 and I29.

To provide for the shifting of the piston .I I8 longitudinally to control the operation of the hydraulic piston motors 3 I and 32, I provide an operating lever I35 which is pivoted to a pin I36 carried by the arms H and provided with an elongated slot I31 adapted to receive a pin I38 which extends through a neck portion I39 of the piston I I8. A cotter key I40 extends through the pin I38 and neck I39 to hold them together.

To provide for automatic centering of the piston II8 I provide a pair of similar spring means I which are coiled about the pin I36 and have upstanding arms adapted to engage alternately the pin I38 and stops I42 carried by the arms II5. It will be evident that the spring means I urge the piston II8 to a neutral position in which the ports I33 and I34 are opposite the chambers I 24 and I25, respectively, and that when said piston I I8 is moved in either direction from this normal position, it will be automatically returned when the moving force is removed.

As clearly illustrated in Fig. 8 of the drawings, there are five operating position for the lever I35 designated N which is the neutral position (see Fig. 16) 3IE which is the position at which hydraulic piston motor 3I.is elevated (see Fig. 15), 32E which is the position at which hydraulic piston motor 32 is elevated (see Fig. 17), 3ID which is the position at which hydraulic piston motor 3I is discharged (see Fig. 14), and 32D which is the position at which hydraulic piston motor 32 is discharged (see Fig. 18). When the lever I35 is in the neutral or N position, with piston H8 in the position illustrated in Fig. 16, the port I43 will be aligned with the bore I and oil under pressure from the line I02 will flow through the boss I03, passages I22 and I23 in parallel, chambers I24 and I25, ports I33 and I34 to bore I 3| from which it will be discharged by port I43 through said bore I30 into the sump 91 of the compartment 1 I. It will thus be seen that in this condition the pump 14 will have a substantially no-load by-pass whereby the out-put of .oil therefrom will flow freely to the sump 91 and thus the pump will not be required to do work which serves no useful purpose.

When the lever I is moved forward to position 32E with piston H8 in the position illustrated in Fig. 1'1, communication is provided from pressure pipe I02 through boss I03, passage I23, chamber I25, through port I43 which is now in alignment with chamber I25, through bore I3I, port I34, to chamber I29 from which it flows through passage I28 in boss I2I to feed pipe I08 connected to hydraulic piston motor 32. It is evident that when this oil under pressure is supplied above the piston of said piston motor 32, said piston will be moved downwardly thereby to elevate that side of the mining machine by virtue of the downward movement of the skid 30 with respect thereto. In said position 32E it may be noted that the port I33 is in the plane of the bore I30 but since they extend at right angles to each other no communication is rovided between them and port I33 is eifeotively sealed.

By moving the lever I35 to the position 3213 with piston H8 in the position illustrated in Fig. 18 the oil in the hydraulic piston motor 32 is allowed to discharge under the pressure caused by the weight of the mining machine thereon, the discharge passageway being from feed pipe I08 to chamber I29 by way of passage I28, through port I43 which is In alignment with chamber I29, through bore I3I and out of port' I34 into the sump 91, since port I 34 in this position extends beyond th forward extremity of the cylindrical member I I6 and is exposed to atmosphere in the compartment 1I.

When the lever I35 is moved to the position 3IE with piston H8 in the position illustrated in Fig. 15 pressure from the pressure pipe I02 flows through boss I03, passage I22, chamber I24, port I43, bore I3I, port I33, chamber I21 to feed passage I26 in boss I20, thence by feed pipe I05 to the hydraulic piston motor 3|. This oil under pressure supplied to piston motor 3I will force the piston 36 thereof downwardly relative to the mining machine thus causing elevation of that side of the mining machine through the skid 29.

To discharge the hydraulic fluid from the hydraulic piston motor 3I the lever I35 i moved to position 3ID with piston H8 in the position illustrated in Fig. 14 in which position the fluid can flow therefrom through the feed pip I05 to chamber I21 which now communicates with port I 43 leading to bore I3I and through port I33 to the chamber 1I thus providing for free discharge of the hydraulic fluid into the sump 91.

It may also be mentioned that when the lever I35 is in the position 3ID or 32D to discharge the fluid from the hydraulic piston motors 3I or 32, respectively, there will be a by-pass for the pump 14 to prevent it operating under load while no useful work is being performed. This is evident from a consideration of Figs. 8 and 14 of the drawings in which the control valve I04 is illustrated in position 3ID and which 011 under pressure from the pipe I02 is free to flow to the passage I22, chamber I24, port I34, bore I3I and into the compartment H by way of port I33.

When the lever I35 is in the position 32D illustrated in Fig. 18, the by-pass for the pump 14 is provided from the pressure pipe I02 through passage I23, chamber I25, port I33 in alignment therewith, bore I3I and out port I34 into chamber 1|.

It is thus to be seen that the continuously operating pump 14 is provided with a no-load by-pass not only for the normal or non-operating position of the control valve I04, but also for thepositions thereof in which the hydraulic piston motors 3| and 32 are being discharged.

It is also to be noted that when the lever I35 is in the neutral position a no-load by-pass is not only provided for the pump 14, but both of the hydraulic piston motors 3I and 32 are locked in their selected positions. This is due to the fact that when said'lever I 35 is in the neutral position there is no port I33, I34 or I43 in communlcation other words, under these conditions the chambers I21 and I29 are sealed, thereby sealing the oil in the hydraulic piston motors-3| and 32.

It is of importance to note that in the'operation of the control valve I04 from the neutral position in either direction, the first position encountered is one to expand the hydraulic pistonmotor 3| or 22 and the second position is one to discharge the hydraulic piston motor 3| or 32. As a consequence, either hydraulic motor 3I or 32 may be operated to a desired position of elevation of the mining machine whereupon the lever I35 will be released and automatically returned to its neutral position tolock the operated motor in its position of adjustment without passing througha release or discharge position for said hydraulic piston motor.

vTo provide for the control of the lever I 35 from a position adjacent the tail section 2| where the other controls for the mining machine are assembled, I provide a longitudinally ex tending rod I44 having a head I45 Whichls attached to said rod I44 by a pin I45. The head I45 is provided with an elongated slot -I4I adapted to receive a pin I48 carried by the upper end of the lever I35 and providing a pivotal sliding connection between the rod I44 and the lever I35. Cotter keys I49 are provided to maintain the pin I48 in place.

The rod I44 extends from the head section 23 through the motor section 22 and to a position at the forward end clearly illustrated in Fig.1 of the drawings.

As best seen by reference to Figs. 1 and of the drawings, the rod I44 is provided with a pair of spaced notches I50 adapted to latch over an edge I5I of a housing I52 adjacent the forward end of said tail section 2|. The notches I50 are so positioned as to correspond with. positions ME and 32E of the lever I35. As a consequence, said notches I50 serve the double purpose of indicating to an operator who is operating the rod I44 that the lever I35 is in the position 3IE or 32E, and of latching said lever I35 in either position 3IE or 32E so that continued expansion of a hydraulic piston motor 3I or 32 may be continued without requiring the operator to hold the rod I 44 manually in motor expanding position. In other words, for the operator to expand a hydraulic piston motor 31 or 32 it is only necessary to move the rod I44 forwardly or rearwardly from its neutral position and to latch a notch I50 over the edge I5I. When this interlocking relation is released the lever I35 will automatically return to its neutral position, as previously described.

To aid in the operation of the rod I44 said rod is provided with a cross-pin I53 which provides a handle to be grasped by the operator.

In the operation of the device comprising my invention, it will be evident that the electric motor carried by the motor section 22 will drive the eccentric cam 89 whenever the motor is in operation, as a consequence of which the pump I4 is a continuously operating pump and provides fluid pressure at all times duringthe opera tion of said motor. The drive for the kerf-cut-' ting mechanism is selectively controllable and is driven from the same electric motorthrougb with the chambers I2I or I29.. In

of the tail section 2.I, as V the gear train including the vertical drive shaft 53 and the sprocket 52.

The available hydraulic liquid under pressure from the pump I4 can be supplied at will by the operator by operating the rod I44 to expand selectively the hydraulic piston motors II and 32. It is furthermore to be noted that said hydraulic piston motors 3| and 32 are automatically locked in any expanding position upon release of the rod I44. It is thus possible to adjust the level of the mining machine and consequently the level of the cutter bar 44 in both longitudinal and transverse planes, thus to accommodate the mining machine to an uneven mine floor or to an uneven seam of coal or other material which is to be cut out.

It .is further evident that the operator may discharge the fluid from the hydraulic piston motors 3I and 32 selectively by operation of the same rod I44. It is thus manifest that a very flexible control for the levelling of the mining machine and cutter bar is provided and one which requires no appreciable effort or skill on the part of the operator.

It is furthermore to be noted that the hydraulic system is operative at all times to provide pressure when useful work is to be done, yet when no useful work is being done thepump of said system operates at substantially no-load.

It is still further to be noted that the hydraulic I In this connection it may particularlybe noted that there are no pipes of the hydraulic control system which are directly exposed or subject said pipes being completely enclosed within the housing of the head section 23.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of the invention-as defined by the claims hereto appended, and I therefore wish not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodiment of my invention, what I desire to secure by Letters Patent of the United States is:

1. Apparatus of the class described comprising the combination with a pair of fluid-presapparatus, of a power-driven pump, controlling pump to said motors and comprising a control valve having five positions including a neutral position, a motor actuating position for each motor and a motor discharging movement of the valve to both motors are locked in the pump is provided with neutral position while adjusted positions and a no-load by-pass.

2. In apparatus of combination with a pair of hydraulic motors, of

a hydraulic system for controlling said motors discharging position for each motor, said posiupon release of said actu-v the class described, the

said conduit and one end 01 said block to pro-- vide flow chambers, a supply conduit connecting the pump to one of said chambers; a motor conduit connected to the other chamber, a valve element slidable along said guideway and provided with an internal longitudinal bore closed at its ends and having radial passageways leading therefrom, said radial passageways being successively out phase relation but spaced to correspond with the spacing between the firstnamed conduit and said chambers, and mechanism for sliding said valve to three predetermined positions of control, one position being to connect the said supply conduit to one of said chambers and thence through one of said radial passageways and through the bore to another of said radial passageways to the other chamber and to the motor conduit, another position being to connect said supply conduit to one of said chambers and thence through one of said radial passageways to said bore and to another radial passageway to the valve block conduit leading to the atmosphere, and the third position being to connect the motor conduit to one of said chambers and one of said radial passageways and thence through said bore to another radial passageway then exposed to the atmosphere.

4. 1n valve mechanism-for apparatus of the class described, the combination with a valve block having a bore, of a valve stem slidable along and through said bore, said block having a port extending from said bore to the atmosphere intermediate the ends of said block and circular recesses near the ends of said block and near the center of said block and said valve stem having a longitudinal recess therein with three spaced ports extending radially from such recess, the intermediate one only being capable of registering with the said port to the atmosphere, delivery ports connected to those circular recesses near the ends of the block, and a supply port connected by branching conduits to those circular recesses near the center of the block, the construction and arrangement being such that when the valve stem is in neutral position the supply port is connected to the port opening to the atmosphere and when the valve stem is in an operating position the port to the atmosphere is cut ofi and the supply port is connected to one of the delivery ports.

5. Apparatus of the class described comprising the combination with a pair of adjustable hydraulic motors, a power driven operating pump, control valve mechanism, conduitsand connections affording said control valve mechanism with five positions including an intermediate neutral position and two motor actuating positions and two motor discharging positions, one motor having an actuating valve position and a discharging valve position on one side of the valve neutral position and the other motor having an actuating valve position and a discharging valve position on the other side of the valve neutral position, the construction and arrangement being such that when the valve mechanism is ln neutral position both of said hydraulic motors are locked in adjusted positions.

ROBERT K. JEFFREY. 

